Systems and methods for determining position and velocity of a handheld device

ABSTRACT

Embodiments of the present invention provide a handheld device that comprises an information module for obtaining and/or receiving information pertaining to a surface adjacent to the device, and a position determination arrangement for determining at least one of a position and/or velocity of the handheld device. The position determination arrangement comprises a determination module configured to determine at least one of a relative position of the handheld device and/or a velocity of the handheld device based upon at least one of surface markings located on the surface adjacent the device and/or apparatus markings located on an input apparatus. The surface markings and the apparatus markings are configured to provide absolute position information.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of non-provisional applicationSer. No. 12/200,717, filed Aug. 28, 2008 entitled, “SYSTEMS AND METHODSFOR DETERMINING POSITION AND VELOCITY OF A HANDHELD DEVICE,” now U.S.Pat. No. 7,773,796, issued Aug. 10, 2010, which claims priority to U.S.Provisional Patent Application No. 60/968,480, filed Aug. 28, 2007,entitled “True X-Y Position, Velocity and Angular Determination ofRandom Motion Devices Using the Integration of Roller Ball and OpticalNavigation Technologies,” the entire specification of which is herebyincorporated by reference in its entirety for all purposes, except forthose sections, if any, that are inconsistent with this specification.

TECHNICAL FIELD

Embodiments of the present invention relate to the field of imagetranslation and, more particularly, to determining positioning of ahandheld image translation device.

BACKGROUND

Traditional printing devices rely on a mechanically operated carriage totransport a print head in a linear direction as other mechanics advancea medium in an orthogonal direction. As the print head moves over themedium an image may be laid down. Portable printers have been developedthrough technologies that reduce the size of the operating mechanics.However, the principles of providing relative movement between the printhead and medium remain the same as traditional printing devices.Accordingly, these mechanics limit the reduction of size of the printeras well as the material that may be used as the medium.

Handheld printing devices have been developed that ostensibly allow anoperator to manipulate a handheld device over a medium in order to printan image onto the medium. However, these devices are challenged by theunpredictable and nonlinear movement of the device by the operator. Thevariations of operator movement, including rotation of the deviceitself, make it difficult to determine the precise location of the printhead. This type of positioning error may have deleterious effects of thequality of the printed image.

Certain handheld scanners have been developed for acquiring an imagefrom a target media. During a scan, image data is recorded by imagesensors along with positioning data by positioning sensors, whichbracket the image sensors. The accumulated image data is position-taggedand recorded as distorted image data. Once the distorted image data hasbeen acquired, it will be processed to provide a rectified image thatcorrects for rotational distortions. This rectification process furtherrelies on overlapping regions of acquired image data to facilitate thestitching of the final image.

While this process may work in a scanning scenario, a printing scenariopresents other challenges. For example, in a printing operation thepositioning of a handheld printing device may not be postponed untilafter a medium has been fully scanned. Furthermore, stitching of acaptured image may also not be available.

SUMMARY

In accordance with various embodiments, a handheld device comprises aninformation module for obtaining and/or receiving information pertainingto a surface adjacent to the device, and a position-determinationarrangement for determining at least one of a position and/or velocityof the handheld device. The position-determination arrangement comprisesa determination module configured to determine the position and/orvelocity of the handheld device based upon at least one of surfacemarkings located on the surface adjacent the device and/or apparatusmarkings located on an input apparatus, wherein the surface markings andapparatus markings are configured to provide absolute positioninformation relative to the handheld device.

In accordance with various embodiments, the input apparatus comprises aroller ball supported within a frame and including the apparatusmarkings, at least three bearings to movably support the roller ballwithin the frame, and at least two sensors to read the apparatusmarkings. In accordance with various embodiments, the at least twosensors comprise a CMOS imaging sensor.

In accordance with various embodiments, the input apparatus furthercomprises at least one cleaning bracket adjacent to the roller ball. Inaccordance with some embodiments, the handheld device comprises at leasttwo input apparatus. In accordance with some embodiments, the handhelddevice comprises at least four input apparatus.

In accordance with various embodiments, the apparatus markings comprisepatterns painted on a surface of the roller ball. In accordance withsome embodiments, the apparatus markings comprise patterns embedded in asurface of the roller ball.

In accordance with some embodiments, the determination module comprisesat least two image sensors configured to read pre-printed patterns froman adjacent surface. In accordance with some embodiments, the at leasttwo image sensors are infra-red CMOS sensors.

In accordance with various embodiments, the handheld device is aprinter. In accordance with some embodiments, the handheld device is ascanner. In accordance with some embodiments, the handheld device is animage translation device configured to print and to scan.

In accordance with various embodiments, the determination module isfurther configured to determine a predictive position of the handhelddevice. In accordance with some embodiments, the determination module isconfigured to determine the predictive position of the handheld deviceusing a two dimensional parametric curve function. In accordance withsome embodiments, the two dimensional parametric curve function is aCatmull-Rom Bicubic Spline function.

The present invention also provides a method comprising moving ahandheld device over a surface, reading markings on at least one of thesurface and/or an input apparatus, wherein the markings are configuredto provide absolute position information, and determining at least oneof a position and/or and angle and/or a velocity of the handheld devicebased upon the reading of the markings.

In accordance with various embodiments, the method further comprisesdepositing a printing substance on the surface. In accordance withvarious embodiments, the method further comprises using an imagerepresentation to determine a level of deposition of the printingsubstance. In accordance with various embodiments, the method furthercomprises using an image representation that is modified as the printingsubstance is deposited. In accordance with some embodiments, the methodfurther comprises scanning information from the surface. In accordancewith various embodiments, the method further comprises removingdistortion from a scanned image. In accordance with various embodiments,the method further comprises stitching scanned information to form acomplete scanned image.

In accordance with various embodiments, the markings are read from atrack ball included in the input apparatus. In accordance with variousembodiments, further comprises cleaning the track ball as the handhelddevice is moved.

In accordance with various embodiments, the markings are read from thesurface. In accordance with various embodiments, the markings are readfrom the surface and from a track ball included in the input apparatus.

In accordance with various embodiments, the method further comprisesdetermining a predictive position of the handheld device. In accordancewith some embodiments, the predictive position is determined using a twodimensional parametric curve function. In accordance with variousembodiments, the two dimensional parametric curve function is aCatmull-Rom Bicubic Spline function.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will be readily understood by thefollowing detailed description in conjunction with the accompanyingdrawings. To facilitate this description, like reference numeralsdesignate like structural elements. Embodiments of the invention areillustrated by way of example and not by way of limitation in thefigures of the accompanying drawings.

FIG. 1 is a schematic of a system including a handheld image translationdevice in accordance with various embodiments of the present invention;

FIG. 2 is a bottom plan view of a handheld image translation device inaccordance with various embodiments of the present invention;

FIG. 3 is a top plan view of a handheld image translation device inaccordance with various embodiments of the present invention;

FIG. 4 is a flow diagram depicting a positioning operation of a handheldimage translation device in accordance with various embodiments of thepresent invention;

FIG. 5 is a graphic depiction of a positioning operation of a handheldimage translation device in accordance with various embodiments of thepresent invention;

FIG. 6 schematically illustrates an example of an IR tag pattern inaccordance with various embodiments of the present invention;

FIG. 7 schematically illustrates an example of a position path;

FIG. 8 schematically illustrates regions for ArcTan ratio;

FIG. 9 schematically illustrates an input arrangement for a handhelddevice for determining position, angle and/or velocity of the handhelddevice in accordance with various embodiments of the present invention;

FIG. 10 schematically illustrates a top view of the input arrangementillustrated in FIG. 9 in accordance with various embodiments of thepresent invention;

FIG. 11 is a flow diagram depicting a printing operation of a handheldimage translation device in accordance with various embodiments of thepresent invention; and

FIG. 12 illustrates a computing device capable of implementing a controlblock of a handheld image translation device in accordance with variousembodiments of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

In the following detailed description, reference is made to theaccompanying drawings which form a part hereof wherein like numeralsdesignate like parts throughout, and in which is shown by way ofillustration embodiments in which the invention may be practiced. It isto be understood that other embodiments may be utilized and structuralor logical changes may be made without departing from the scope of thepresent invention. Therefore, the following detailed description is notto be taken in a limiting sense, and the scope of embodiments inaccordance with the present invention is defined by the appended claimsand their equivalents.

Various operations may be described as multiple discrete operations inturn, in a manner that may be helpful in understanding embodiments ofthe present invention; however, the order of description should not beconstrued to imply that these operations are order dependent.

The description may use perspective-based descriptions such as up/down,back/front, and top/bottom. Such descriptions are merely used tofacilitate the discussion and are not intended to restrict theapplication of embodiments of the present invention.

For the purposes of the present invention, the phrase “A/B” means A orB. For the purposes of the present invention, the phrase “A and/or B”means “(A), (B), or (A and B).” For the purposes of the presentinvention, the phrase “at least one of A, B, and C” means “(A), (B),(C), (A and B), (A and C), (B and C), or (A, B and C).” For the purposesof the present invention, the phrase “(A)B” means “(B) or (AB)” that is,A is an optional element.

The description may use the phrases “in an embodiment,” or “inembodiments,” which may each refer to one or more of the same ordifferent embodiments. Furthermore, the terms “comprising,” “including,”“having,” and the like, as used with respect to embodiments of thepresent invention, are synonymous.

FIG. 1 is a schematic of a system 100 including a handheld imagetranslation (IT) device 104 in accordance with various embodiments ofthe present invention. The IT device 104 may include a control block 108with components designed to facilitate precise and accurate positioningof input/output (I/O) components 112 throughout an entire IT operation.This positioning may allow the IT device 104 to reliably translate animage in a truly mobile and versatile platform as will be explainedherein.

Image translation, as used herein, may refer to a translation of animage that exists in a particular context (e.g., medium) into an imagein another context. For example, an IT operation may be a scanoperation. In this situation, a target image, e.g., an image that existson a tangible medium, is scanned by the IT device 104 and an acquiredimage that corresponds to the target image is created and stored inmemory of the IT device 104. For another example, an IT operation may bea print operation. In this situation, an acquired image, e.g., an imageas it exists in memory of the IT device 104, may be printed onto amedium.

The control block 108 may include a communication interface 116configured to communicatively couple the control block 108 to an imagetransfer device 120. The image transfer device 120 may include any typeof device capable of transmitting/receiving data related to an image, orimage data, involved in an IT operation. The image transfer device 120may include a general purpose computing device, e.g., a desktopcomputing device, a laptop computing device, a mobile computing device,a personal digital assistant, a cellular phone, etc. or it may be aremovable storage device, e.g., a flash memory data storage device,designed to store data such as image data. If the image transfer device120 is a removable storage device, e.g., a universal serial bus (USB)storage device, the communication interface 116 may be coupled to aport, e.g., USB port, of the IT device 104 designed to receive thestorage device.

The communication interface 116 may include a wireless transceiver toallow the communicative coupling with the image transfer device 120 totake place over a wireless link. The image data may be wirelesslytransmitted over the link through the modulation of electromagneticwaves with frequencies in the radio, infrared or microwave spectrums.

A wireless link may contribute to the mobility and versatility of the ITdevice 104. However, some embodiments may additionally/alternativelyinclude a wired link communicatively coupling the image transfer device120 to the communication interface 116.

In some embodiments, the communication interface 116 may communicatewith the image transfer device 120 through one or more wired and/orwireless networks including, but not limited to, personal area networks,local area networks, wide area networks, metropolitan area networks,etc. The data transmission may be done in a manner compatible with anyof a number of standards and/or specifications including, but notlimited to, 802.11, 802.16, Bluetooth, Global System for MobileCommunications (GSM), code-division multiple access (CDMA), Ethernet,etc.

When the IT operation includes a print operation, the communicationinterface 116 may receive image data from the image transfer device 120and transmit the received image data to an on-board image processingmodule 128. The image processing module 128 may process the receivedimage data in a manner to facilitate an upcoming printing process. Imageprocessing techniques may include dithering, decompression, half-toning,color plane separation, and/or image storage. In various embodimentssome or all of these image processing operations may be performed by theimage transfer device 120 or another device. The processed image maythen be transmitted to an I/O module 132, which may function as a printmodule in this embodiment, where it is cached in anticipation of theprint operation.

The I/O module 132, which may be configured to control the I/Ocomponents 112, may receive positioning information indicative of aposition of a print head of the I/O components 112 relative to areference location from a position module 134. The position module 134may control one or more navigation sensors 138 to capture navigationalmeasurements to track incremental movement of the IT device 104 relativeto the reference location.

In some embodiments, the navigational measurements may be navigationalimages of a medium adjacent to the IT device 104. In these embodiments,the navigation sensors 138 may include one or more imaging navigationsensors. An imaging navigation sensor may include a light source, e.g.,light-emitting diode (LED), a laser, etc., and an optoelectronic sensordesigned to capture a series of navigational images of an adjacentmedium as the IT device 104 is moved over the medium. In accordance withvarious embodiments of the present invention, the navigation sensors 138comprise infrared complimentary metal oxide semiconductor (IR CMOS)sensors, also known in the art as IR Cameras.

The position module 134 may process the navigational images to detectstructural variations of the medium. The movement of the structuralvariations in successive images may indicate motion of the IT device 104relative to the medium. Tracking this relative movement may facilitatedetermination of the precise positioning of the navigation sensors 138.The navigation sensors 138 may be maintained in a structurally rigidrelationship with the I/O components 112, thereby allowing for thecalculation of the precise location of the I/O components 112.

The navigation sensors 138 may have operating characteristics sufficientto track movement of the image translation device 104 with the desireddegree of precision. In one example, imaging navigation sensors mayprocess approximately 2000 frames per second, with each frame includinga rectangular array of 30×30 pixels. Each pixel may detect a six-bitgrayscale value, e.g., capable of sensing 64 different levels ofpatterning.

Once the I/O module 132 receives the positioning information it maycoordinate the location of the print head to a portion of the processedimage with a corresponding location. The I/O module may then control theprint head of the I/O components 112 in a manner to deposit a printingsubstance on the medium adjacent to the IT device 104 to represent thecorresponding portion of the processed image.

The print head may be an inkjet print head having a plurality of nozzlesdesigned to emit liquid ink droplets. The ink, which may be contained inreservoirs or cartridges, may be black and/or any of a number of variouscolors. A common, full-color inkjet print head may have nozzles forcyan, magenta, yellow, and black ink. Other embodiments may utilizeother printing techniques, e.g., toner-based printers such as laser orLED printers, solid ink printers, dye-sublimation printers, inklessprinters, etc.

In an embodiment in which an IT operation includes a scanning operation,the I/O module 132 may function as an image capture module and may becommunicatively coupled to one or more optical imaging sensors of theI/O components 112. Optical imaging sensors, which may include a numberof individual sensor elements, may be designed to capture a plurality ofsurface images of a medium adjacent to the IT device 104. The surfaceimages may be individually referred to as component surface images. TheI/O module 132 may generate a composite image by stitching together thecomponent surface images. The I/O module 132 may receive positioninginformation from the position module 134 to facilitate the arrangementof the component surface images into the composite image.

Relative to the imaging navigation sensors, the optical imaging sensorsmay have a higher resolution, smaller pixel size, and/or higher lightrequirements. While the imaging navigation sensors are configured tocapture details about the structure of the underlying medium, theoptical imaging sensors may be configured to capture an image of thesurface of the medium itself.

In an embodiment in which the IT device 104 is capable of scanning fullcolor images, the optical imaging sensors may have sensor elementsdesigned to scan different colors.

A composite image acquired by the IT device 104 may be subsequentlytransmitted to the image transfer device 120 by, e.g., e-mail, fax, filetransfer protocols, etc. The composite image may beadditionally/alternatively stored locally by the IT device 104 forsubsequent review, transmittal, printing, etc.

In addition (or as an alternative) to composite image acquisition, animage capture module may be utilized for calibrating the position module134. In various embodiments, the component surface images (whetherindividually, some group, or collectively as the composite image) may becompared to the processed print image rendered by the image processingmodule 128 to correct for accumulated positioning errors and/or toreorient the position module 134 in the event the position module 134loses track of its reference point. This may occur, for example, if theIT device 104 is removed from the medium during an IT operation.

The IT device 104 may include a power supply 150 coupled to the controlblock 108. The power supply 150 may be a mobile power supply, e.g., abattery, a rechargeable battery, a solar power source, etc. In otherembodiments the power supply 150 may additionally/alternatively regulatepower provided by another component (e.g., the image transfer device120, a power cord coupled to an alternating current (AC) outlet, etc.).

FIG. 2 is a bottom plan view of an IT device 200 in accordance withvarious embodiments of the present invention. The IT device 200, whichmay be substantially interchangeable with IT device 104, may have afirst navigation sensor 204, a second navigation sensor 208, and a printhead 212. Those skilled in the art will understand that more or fewernavigation sensors may be included as desired depending upon theapplication.

The navigation sensors 204 and 208 may be used by a position module,e.g., position module 134, to determine positioning information relatedto the print head 212. As stated above, the proximal relationship of theprint head 212 to the navigation sensors 204 and 208 may be fixed tofacilitate the positioning of the print head 212 through informationobtained by the navigation sensors 204 and 208.

The print head 212 may be an inkjet print head having a number of nozzlerows for different colored inks. In particular, and as shown in FIG. 2,the print head 212 may have a nozzle row 212 c for cyan-colored ink, anozzle row 212 m for magenta-colored ink, a nozzle row 212 y foryellow-colored ink, and nozzle row 212 k for black-colored ink.

While the nozzle rows 212 c, 212 m, 212 y, and 212 k shown in FIG. 2 arearranged in rows according to their color, other embodiments mayintermix the different colored nozzles in a manner that may increase thechances that an adequate amount of appropriate colored ink is depositedon the medium through the natural course of movement of the IT device200 over the medium.

In another embodiment, the IT device 200 may include optical imagingsensors adjacent to the nozzle rows.

FIG. 3 is a top plan view of the IT device 200 in accordance withvarious embodiments of the present invention. The IT device 200 may havea variety of user input/outputs to provide the functionality enabledthrough use of the IT device 200. Some examples of input/outputs thatmay be used to provide some of the basic functions of the IT device 200include, but are not limited to, an IT control input 304 toinitiate/resume a print and/or scan operation and a display 308.

The display 308, which may be a passive display, an interactive display,etc., may provide the user with a variety of information. Theinformation may relate to the current operating status of the IT device200 (e.g., printing, scanning, ready to print, ready to scan, receivingimage data, transmitting image data, etc.), power of the battery, errors(e.g., positioning/printing/scanning error, etc.), instructions (e.g.,“place IT device on medium prior to initiating IT operation,” etc.). Ifthe display 308 is an interactive display it may provide a controlinterface in addition to, or as an alternative from, the IT controlinput 304.

FIG. 4 is a flow diagram 400 depicting a positioning operation of the ITdevice 200 in accordance with various embodiments of the presentinvention. A positioning operation may begin at block 404 with aninitiation of a printing operation, e.g., by activation of the ITcontrol input 304. A position module within the IT device 200 may set areference location at block 408. The reference location may be set whenthe IT device 200 is placed onto a medium at the beginning of an IToperation. This may be ensured by the user being instructed to activatethe IT control input 304 once the IT device 200 is in place and/or bythe proper placement of the IT device 200 being treated as a conditionprecedent to instituting the positioning operation. In some embodimentsthe proper placement of the IT device 200 may be automaticallydetermined through the navigation sensors 204 and/or 208 and/or someother sensors (e.g., a proximity sensor).

Once the reference location is set at block 408, the position module maydetermine positioning information, e.g., translational and rotationalchanges from the reference location, using the navigation sensors 204and 208, and transmit the determined positioning information to an I/Omodule at block 412. The translational changes may be determined bytracking incremental changes of the positions of a navigation sensoralong a two-dimensional coordinate system, e.g., Δx and Δy. Rotationalchanges may refer to changes in the angle of the IT device 200, e.g.,ΔΘ, with respect to, e.g., the y-axis. These transitional and/orrotational changes may be determined by the position module comparingconsecutive navigational measurements taken by the navigation sensors204 and 208 to detect these movements. This process may be furtherexplained by reference to FIG. 5 and corresponding discussion.

While embodiments of the present invention discuss tracking an IT devicein a two-dimensional coordinate system, other embodiments may includetracking within a three-dimensional coordinate system.

FIG. 5 is a graphic depiction of a positioning operation of the ITdevice 200 in accordance with embodiments of the present invention. Atinitiation, e.g., t=0, the sensors 204 and 208 may be in an initialposition indicated by 204(t=0) and 208(t=0), respectively. Oversuccessive time intervals, e.g., t=1-4, the sensors 204 and 208 may bemoved to an end position indicated by 204(t=4) and 208(t=4),respectively. As used in description of this embodiment, the “initialposition” and the “end position” are used merely with reference to thisparticular operation and not necessarily the start or end of theprinting operation or even other positioning operations.

As the sensors 204 and 208 are moved, they may capture navigationalmeasurements at each of the indicated time intervals, e.g., t=0-4. Thecapture period may be synchronized between the sensors 204 and 208 by,e.g., hardwiring together the capture signals transmitted from theposition module. The capture periods may vary and may be determinedbased on set time periods, detected motion, or some other trigger. Insome embodiments, each of the sensors 204 and 208 may have differentcapture periods that may or may not be based on different triggers.

The captured navigational measurements may be used by the positionmodule to determine a translation of the IT device 200 relative to areference location, e.g., the sensors 204(t=0) and 208(t=0) as well as arotation of the IT device 200. In some embodiments, the translation ofthe device 200 may be determined by analyzing navigational measurementsfrom a first sensor, e.g., sensor 204, while the rotation of the device200 may be determined by analyzing navigational measurements from asecond sensor, e.g., sensor 208. In particular, and in accordance withsome embodiments, the rotation of the IT device 200 may be determined bycomparing translation information derived from the navigationalmeasurements provided by sensor 208 to translation information derivedfrom navigational measurements provided by sensor 204. Determining boththe translation and the rotation of the IT device 200 may allow theaccurate positioning of all of the nozzles of the print head 212.

The translation of the sensors 204 and 208 may be determined within thecontext of a world-space (w-s) coordinate system, e.g., a Cartesiancoordinate system. In particular, the translation values may bedetermined for two-dimensions of the w-s coordinate system, e.g., thex-axis and the y-axis as shown in FIG. 5. For example, the positionmodule may accumulate the incremental Δx's and Δy's between successivetime periods in order to determine the total translation of the sensors204 and 208 from time zero to time four. The accumulated changes forsensor 204 may be referred to as Δx₁ and Δy₁ and the accumulated changesfor sensor 208 may be referred to as Δx₂ and Δy₂. The sensors 204 and208 may be a distance d from one another. The rotation Θ of the ITdevice 200 may then be determined by the following equation:

$\begin{matrix}{{\theta = {\sin^{- 1}\left( \frac{{{\Delta\; x_{2}} - {\Delta\; x_{1}}}}{d} \right)}},} & {{Eq}.\mspace{14mu} 1.}\end{matrix}$

In some embodiments, each of the sensors 204 and 208 may reportincremental delta values within their respective coordinate systems,which may then be mapped to the w-s coordinate system to provide the w-stranslation and/or rotation values. As may be seen from Eq. 1, therotation Θ is derived in part by providing the distance d in thedenominator of the arcsin value. Accordingly, a large distance d mayprovide a more accurate determination of the rotation Θ for a givensensor resolution. Therefore, in designing the IT device 200, thedistance d may be established based at least in part on the resolutionof the data output from the sensors 204 and 208. For example, if thesensors 204 and 208 have a resolution of approximately 1600 counts perinch, the distance d may be approximately two inches. In an embodimenthaving this sensor resolution and distance d, the rotation Θ may bereliably calculated down to approximately 0.0179 degrees.

While the embodiment shown in FIG. 2 illustrates the sensors 204 and 208located on a first side of the print head 212, other configurations maybe employed while still maintaining the desired distance d. For example,the sensors 204 and 208 may be on opposite sides of the print head 212.The configuration employed may be selected based on objectives of aparticular embodiment. For example, disposing both sensors 204 and 208on the same side of the print head 212 may limit the potential for inkcontamination on the sensors 204 and 208 when printing and may allowmore time for ink to dry on the medium before a second print pass ismade in the same area, where the wet medium may induce more drag whenthe unit passes through the partially printed zone. In another example,placing the sensors 204 and 208 on opposite sides of the print head 212may facilitate a detection of an edge of the medium.

Referring again to FIG. 4, following position determination at block412, the position module may determine whether the positioning operationis complete at block 416. If it is determined that the positioningoperation is not yet complete, the operation may loop back to block 412.If it is determined that it is the end of the positioning operation, theoperation may end in block 420. The end of the positioning operation maybe tied to the end of a printing operation, which is further describedherein with reference to FIG. 11.

In accordance with various embodiments of the present invention,pre-marked (pre-tagged) paper using a marking technology that is notvisible to the human eye such as, for example, yellow or infrared on apaper medium is used as a print medium. This pre-tagged medium hasmarkings or tags encoded on its surface that provide absolute X, Yposition information relative to the actual position that the data wasencoded on the medium. To decode or determine the position data,navigation sensors 204 and 208 are CMOS sensors that are able to readthe encoded information on the pre-tagged medium in order to extract theabsolute X, Y position data. Thus, this embodiment of the presentinvention uses CMOS imaging sensors tuned to the light wave of theencoded marking on the medium that may read the absolute encoded X, Yposition information on the medium while the IT device 200 is in motion.This embodiment allows the IT device 200 to extract absolute positioninformation for each position measurement. With this type of approach,the position errors are generally not cumulative. As with theembodiments that use optical navigation technology, this embodimentagain includes a configuration using two sensors 204 and 208 that eachprovides the absolute X, Y position data that is then used to calculatethe angular accuracy for the print head position that is desired inorder to support printing. Additionally, velocity of the IT device 200may also be determined by calculating the changes in position and thetime involved with the changes in position.

Thus, in this type of embodiment, the print medium needs to bepre-printed with the tag information. In accordance with variousembodiments, the marking information is infrared encoding and thus, thenavigation sensors 204 and 208 are IR CMOS imaging sensors that maycapture the IR signature that is only readable under IR illumination(and therefore not visible to the human eye). The IR signature or taginformation may consist of a regular pattern and a field of digitallyencoded data. The regular pattern may be used to determine small scaleposition offsets and rotation. The data may provide the absoluteposition on the medium. An example of IR CMOS sensors and pre-taggedpaper technology is provided by Silverbrook research in Sydney,Australia. FIG. 6 illustrates an example of an IR tag pattern. Thepre-printed tags are processed to yield an overall position and angle ofeach sensor 204 and 208. The position information of the two sensors 204and 208 is used to create a composite position and rotation of the ITdevice 200 printing system. It should be understood that the tags inFIG. 6 are magnified. In actual use, the tags would be printed with inkthat absorbs in the IR spectrum and not in the visible spectrum makingthe markings invisible to the naked eye.

Since the position information delivered by the sensors 204 and 208 areabsolute with respect to the print medium, very little processing isnecessary to determine the final position information. In accordancewith various embodiments, the position data from the sensors 204 and 208are scaled to a local form of 16.16 integer data. The 16 bit super radixdata is the position in 300th's of an inch to correspond to theresolution of the print system. The two positions are averaged toincorporate the data from both sensors 204 and 208 in the finalposition. Averaging reduces the position noise. The datum of theresultant position is the midpoint between the centers of the twosensors 204 and 208. In accordance with various embodiments of thepresent invention, since the printing system of the IT device 200desires new position data every millisecond or even faster, intermediatepositions are predicted. A simple first order predictive interpolationmay achieve reasonable results. The last two measured positions may beused to compute an X and Y derivative. Interpolated points may becomputed by the following equations:Xi=Xs+dx/dt*ΔT  Eq. 2Yi=Ys+dy/dt*ΔT  Eq. 3

In order to deal with changes in velocity and acceleration, a twodimensional parametric curve function may be employed. The twodimensional parametric curve describes the motion of the IT device 200as a parametric equation with time (t) as the parametric value.X=A _(x) t ³ +B _(x) t ² +C _(x) t+D _(x)Y=A _(y) t ³ +B _(y) t ² +C _(y) t+D _(y)  Eqs. 5 and 6

Equations 5 and 6 represent the form of a BiCubic Spline, a twodimensional parametric curve. In equations 5 and 6, the coefficientscorrespond to the starting position (D), velocity (C), acceleration (B),and the rate change of the acceleration (A) in the X and Y axes. Thereare numerous methods known in the art for determining the coefficientsfor these equations. One well know method, the Catmull Rom BicubicSpline, offers the advantage of ensuring that the resulting equationswill contain the input control points.

Referring to FIG. 7, with a 3rd degree equation, four points aregenerally required to establish all four coefficients for the twoequations. The X and Y axes may be treated separately. The sample pointsmay be taken at equal intervals of time. This helps insure that the arclength of the curve is interpreted correctly. If the points on the curveare at widely varying intervals, then the time domain has to beseparately smoothed to yield correct prediction results.

Although the Catmull Rom Bicubic Spline coefficients help ensure thatthe sampled history will be included in the curve 700 defined by theequations, the Predicted Path portion 702 of the curve will notnecessarily exactly match the actual path. In order to evaluate theperformance of this embodiment, a Predicted Next sample 704 at t+4e maybe compared to a next actual position measured by at least one of thesensors 204 and 208.

To compute an angle of the IT device 200, the difference in the X and Ypositions may be first determined. The X difference is divided by the Ydifference. To accomplish this, the values of X and Y may be adjusted tobest take advantage of limited 32 bit integer arithmetic that may benative to the position module 134.

In accordance with various embodiments, the ratio, X/Y, may be used todetermine the Arc Tangent, for example by looking it up in a table. Theresult of the table lookup is the angle of the IT device 200 withrespect to the pre-printed grid of encoded Tag information on the printmedium. The table may be represented by a range of 0 to 45 degrees in atable that is 16K(K=1024) locations long. The ratio may also berepresented as Y/X, when the X value is larger than the Y value. Thislimits the range of the ratio to numbers that are less than one andavoids the singularity of dividing by zero as the angle approaches 90degrees and 270 degrees. FIG. 8 illustrates regions for the Arc Tangentratio.

Using the position and angle information, the position of the IT device200, and thereby the print head 212, may be determined by the same twodimensional space rotation that was previously described with referenceto FIG. 5 based on a traditional optical navigation based system.

The result is that the position of the printing of IT device 200 isfixed to the print medium. To move the starting position of the image onthe page, a starting position is captured just before printing starts,as previously described with reference to FIG. 4. This initial positionis subtracted from the absolute position, allowing the image to beplaced anywhere on the print medium. In order to print at odd angles,the initial angle of the IT device 200 may be captured. When the printoffset angle is not zero, the position information should be rotated toaffect a rotation of the image on the print medium.

Before the position information is conveyed to the print system, thepositions are rotated about the initial or start position of the image.The result is a position and angle relative print.X _(r) =X*Cos θ−Y*Sin θ  Eq. 7Y _(r) =X*Sin θ+Y*Cos θ  Eq. 8

For convenience, the angle may be snapped to the 0, 90, 180 and 270offsets. To do this, the angle may be forced to one of the 4 snapangles. The “snap” occurs when the angle is within a small range closeto the 90 degree snap angles.

After the position and angle of the IT device 200 is computed by theposition module 134, the information is passed to the print head 212,which may compute the position of every nozzle with respect to the imageand fires the relevant nozzles.

Referring to FIGS. 9 and 10, in accordance with various embodiments ofthe present invention, an input apparatus 900 is illustrated. Thisembodiment is based on a traditional mechanical mouse approach andincludes a roller ball 902 that includes encoded information markings904 on its surface that is read by a CMOS imaging sensor 906 thatincludes both a light source and a sensor as is known in the art. Themarkings 904 include absolute position information that is read by theCMOS imaging sensor 906, which provides absolute position informationrelating to longitudinal and latitudinal position of roller ball 902. Inaccordance with various embodiments, two CMOS imaging sensors 906 may beprovided to improve accuracy. More CMOS imaging sensors 906 may beprovided if desired.

With this embodiment it is not necessary that encoded markings bepresent on the medium, which is desirable in the embodiment where themedium includes the encoded markings. The roller ball 902 is held in theinput apparatus 900 via a mechanical “sandwich” that allows freerotation and couples linear motion to the system. In accordance withvarious embodiments, this arrangement includes a frame 908 to helpstabilize and hold the roller ball 902 in place within the IT device200. Three bearings 910 are provided to cooperate with the frame 908 toprovide movable support. Such an arrangement allows the roller ball tobe free to move within the frame 908 with a level of friction providedin order to provide both user tactical feedback and to prevent theroller ball 902 from have random movement when the IT device 200 islifted from the print medium.

In accordance with various embodiments, a cleaning bracket 912 thatprovides a cleaning material that constantly sweeps the roller ball 902free of contaminants that may negatively impact navigation results maybe provided adjacent to the roller ball 902. The cleaning bracket 912may be a single device that surrounds a portion of the roller ball 902or may consist of multiple devices.

As in previous embodiments, two input arrangements 900 are included (asopposed to two navigation sensors 204 and 208) to calculate the angleinformation associated with a given X, Y position. In accordance withvarious embodiments, four input arrangements 900 are used to act ascontact points to the media surface and to improve positioning accuracy.This provides a way to keep the printing operation planar to the surfacewhere navigation and printing is taking place. As discussed, only two ofthe input arrangements 900 need have the CMOS imaging sensors 906included to detect surface movement and report on actual roller ballposition X,Y data, if desired. Mathematical determination of the X,Yposition, angle and/or velocity of the IT device 200 is then determinedby reading the markings on the roller balls 902 of the inputarrangements 900 with CMOS imaging sensors 906 and is similar to whathas been previously described with reference to reading the pre-taggedmedium that has been encoded with position information with reference toFIGS. 6-8.

In accordance with various embodiments, the roller ball 902 surfacemarkings may be matched with characteristics for a given CMOS imagingsensor 906, both the light source and image sensor. Such optimizationmay take the form of recognizable patterns either painted on or embeddedwithin the roller ball 902 itself. The optimization may also entail atuned light source and image sensor, which may be more delicate than theencoding technology in current devices given that the delicatenavigation sensor elements are protected by the IT device 200 housing.

Those skilled in the art will understand that the IT device 200 may beconfigured with input arrangements 900 and navigation sensors 204 and208 such that IT device 200 may determine position, angle and/orvelocity of the IT device 200 by one or more of the methods describedwith reference to FIGS. 6-10, either separately or concurrently ifdesired.

FIG. 11 is a flow diagram 1100 depicting a printing operation of the ITdevice 200 in accordance with various embodiments of the presentinvention. The printing operation may begin at block 1104. The printmodule may receive a processed image from the image processing module atblock 1108. Upon receipt of the processed image, the display 308 mayindicate that the IT device 200 is ready for printing at block 1112.

The print module may receive a print command generated from a useractivating the IT control input 304 at block 1116. The print module maythen receive positioning information from the position module at block1120. The print module may then determine whether to deposit printingsubstance at the given position at block 1124. The determination as towhether to deposit printing substance may be a function of the totaldrop volume for a given location and the amount of volume that has beenpreviously deposited.

The print module may make a determination to deposit printing substanceby reading a representation of the printed image in memory. If theprinting module determines that printing substance is to be deposited,it may modify the image representation to account for the amount andlocation of deposited printing substance. The print module may use themodified representation to determine if additional deposition ofprinting substance is required. The print module may use the modifiedrepresentation to alter the amount of printing substance deposited.

If it is determined that no additional printing substance is to bedeposited at block 1124, the operation may advance to block 1128 todetermine whether the end of the print operation has been reached. If itis determined that additional printing substance is to be deposited atblock 1124, the print module may cause an appropriate amount of printingsubstance to be deposited at block 1132 by generating and transmittingcontrol signals to the print head that cause the nozzles to drop theprinting substance.

As can be seen, the position module's determination of the translationand rotation of the IT device 200 is done prior to the print modulecontrolling the print head to deposit a printing substance. In order forthe positioning information to remain relevant to the printdetermination, it may be desirable that the determination of thepositioning information take place as soon as possible after theacquisition of the navigational measurements upon which it is based.Accordingly, the translation and rotation calculations may be done inreal time based on data accumulated up to that point. The rotationcalculations are not determined retroactively based on a comprehensiveaccumulation of translation and image data as is done in prior artscanning devices discussed above.

The determination of whether the end of the printing operation has beenreached at block 1128 may be a function of the total printed volumeversus the total anticipated print volume. In some embodiments the endof the printing operation may be reached even if the total printedvolume is less than the total anticipated print volume. For example, anembodiment may consider the end of the printing operation to occur whenthe total printed volume is ninety-five percent of the total anticipatedprint volume. However, it may be that the distribution of the remainingvolume is also considered in the end of print analysis. For example, ifthe five percent remaining volume is distributed over a relatively smallarea, the printing operation may not be considered to be completed.

In some embodiments, an end of print job may be established by a usermanually cancelling the operation.

If, at block 1128, it is determined that the printing operation has beencompleted, the printing operation may conclude at block 1136.

If, at block 1128, it is determined that the printing operation has notbeen completed, the printing operation may loop back to block 1120.

FIG. 12 illustrates a computing device 1200 capable of implementing acontrol block, e.g., control block 108, in accordance with variousembodiments. As illustrated, for the embodiments, computing device 1200includes one or more processors 1204, memory 1208, and bus 1212, coupledto each other as shown. Additionally, computing device 1200 includesstorage 1216, and one or more input/output interfaces 1220 coupled toeach other, and the earlier described elements as shown. The componentsof the computing device 1200 may be designed to provide the printingand/or positioning functions of a control block of an IT device asdescribed herein.

Memory 1208 and storage 1216 may include, in particular, temporal andpersistent copies of code 1224 and data 1228, respectively. The code1224 may include instructions that when accessed by the processors 1204result in the computing device 1200 performing operations as describedin conjunction with various modules of the control block in accordancewith embodiments of this invention. The processing data 1228 may includedata to be acted upon by the instructions of the code 1224. Inparticular, the accessing of the code 1224 and data 1228 by theprocessors 1204 may facilitate printing and/or positioning operations asdescribed herein.

The processors 1204 may include one or more single-core processors,multiple-core processors, controllers, application-specific integratedcircuits (ASICs), etc.

The memory 1208 may include random access memory (RAM), dynamic RAM(DRAM), static RAM (SRAM), synchronous DRAM (SDRAM), dual-data rate RAM(DDRRAM), etc.

The storage 1216 may include integrated and/or peripheral storagedevices, such as, but not limited to, disks and associated drives (e.g.,magnetic, optical), USB storage devices and associated ports, flashmemory, read-only memory (ROM), non-volatile semiconductor devices, etc.Storage 1216 may be a storage resource physically part of the computingdevice 1200 or it may be accessible by, but not necessarily a part of,the computing device 1200. For example, the storage 1216 may be accessedby the computing device 1200 over a network.

The I/O interfaces 1220 may include interfaces designed to communicatewith peripheral hardware, e.g., I/O components 112, navigation sensors138, etc., and/or remote devices, e.g., image transfer device 120.

In various embodiments, computing device 1200 may have more or lesselements and/or different architectures.

While embodiments of the present invention have been described withrespect to handheld IT devices, those skilled in the art will understandthat various aspects of embodiments may be applied to other types ofhandheld devices.

Although certain embodiments have been illustrated and described hereinfor purposes of description of preferred embodiments, it will beappreciated by those of ordinary skill in the art that a wide variety ofalternate and/or equivalent embodiments or implementations calculated toachieve the same purposes may be substituted for the embodimentsillustrated and described without departing from the scope of thepresent invention. Those with skill in the art will readily appreciatethat embodiments in accordance with the present invention may beimplemented in a very wide variety of ways. This application is intendedto cover any adaptations or variations of the embodiments discussedherein. Therefore, it is manifestly intended that embodiments inaccordance with the present invention be limited only by the claims andthe equivalents thereof.

1. A handheld image translation device comprising: a communicationinterface configured to wirelessly receive image data to be printed ontoa medium, the medium having been previously encoded with markings on asurface of the medium, the markings not being visible to a human eye; aprint head configured to print the image data onto the medium; aposition module configured to determine a position of the handheld imagetranslation device relative to the medium based on the markings locatedon the surface of the medium, wherein the position module is furtherconfigured to predict the position of the handheld device relative tothe medium based on a two dimensional parametric, and wherein the twodimensional parametric curve function is a Catmull-Rom Bicubic Splinefunction; and an input/output module configured to control the printhead during the printing of the image data onto the medium based on theposition of the handheld image translation device relative to themedium.
 2. The handheld image translation device of claim 1, wherein theposition module comprises at least two image sensors configured todetect the markings on the surface of the medium.
 3. The handheld imagetranslation device of claim 2, wherein the at least two image sensorsare infra-red CMOS sensors.
 4. The handheld image translation device ofclaim 1, wherein the handheld image translation device is a printer. 5.The handheld image translation device of claim 1, wherein the handheldimage translation device is a scanner.
 6. A method comprising:wirelessly receiving image data at a handheld image translation deviceto be printed on a medium; moving the handheld image translation deviceover the medium, the medium having been previously encoded with markingson a surface of the medium, the markings not being visible to a humaneye; reading the markings on the surface; determining a position of thehandheld image translation device relative to the medium based upon thereading of the markings; determining a predicted position of thehandheld image translation device using a two dimensional parametriccurve function, wherein the two dimensional parametric curve function isa Catmull-Rom Bicubic Spline function; and printing the image data ontothe medium based on the position of the handheld image translationdevice relative to the medium.
 7. The method of claim 6, furthercomprising using an image representation to determine a level ofdeposition of a printing substance during printing of the image data. 8.The method of claim 7, further comprising using an image representationthat is modified as the printing substance is deposited during theprinting of the image data.
 9. The method of claim 6, further comprisingscanning information from the surface to provide a scanned image. 10.The method of claim 9, further comprising removing distortion from thescanned image.
 11. The method of claim 9, further comprising stitchingthe scanned information to form a complete scanned image.